package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IVoucherService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {


    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    StringRedisTemplate stringRedisTemplate;

    @Resource
    RedissonClient redissonClient;

    @Resource
    private IVoucherOrderService proxy;//定义代理对象，提前定义后面会用到
    //注入脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct//bean构造注入完毕，初始化方法执行前执行
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());

    }

    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while( true){
                //获取队列中的订单信息
                try {
                    VoucherOrder voucherOrder = orderTasks.take();
                    //创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
         //获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        if(!isLock){
            log.error("不允许重复下单");
        }
        try{
            proxy.createVoucherOrder(voucherOrder);


        }
        finally{
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) { //使用lua脚本
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(), //这里是key数组，没有key，就传的一个空集合
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是0
        int r = result.intValue();//Long型转为int型，便于下面比较
        if (r != 0) {
            //2.1 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "优惠券已售罄" : "不能重复购买");

        }
        long orderId = redisIdWorker.nextId("order");

        //保存阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        orderTasks.add(voucherOrder);

        //获取代理对象,提前获取，子线程不行
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }

    @Transactional
    public Result createVoucherOrder(VoucherOrder voucherOrder) {//对同一个用户加锁
        //一人一单
    Long userId = voucherOrder.getUserId();
    Long voucherId = voucherOrder.getVoucherId();
     //保证值一样的时候是一个对象
        //6.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();

        //6.2判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次");
            return Result.fail("用户已经购买过一次");

        }
        //5.扣减库存
        boolean success = seckillVoucherService.update().setSql("stock = stock-1")
                .eq("voucher_id", voucherId).gt("stock", 0)
                .update();
        if (!success) {
            return Result.fail("库存不足");
        }


//        //6.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //6.1订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //6.2用户id
//        Long id = UserHolder.getUser().getId();
//        voucherOrder.setUserId(id);
//        //6.3代金券id
//        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);
        //7.返回订单id
        return Result.ok(voucherOrder);
        //保存秒杀库存到redis;

    }
}
